1. Technical Field of the Invention
The present invention relates to integrated telecommunication systems and, more particularly, to a system and method for providing access to service nodes from entities (e.g., endpoints, terminals, gatekeepers, etc.) disposed in an integrated telecommunications network. The exemplary integrated telecommunications network may comprise a packet-switched network (PSN) coupled to a circuit-switched network (CSN). Also, the network may comprise a PSN portion only.
2. Description of Related Art
Coupled with the phenomenal growth in popularity of the Internet, there has been a tremendous interest in using packet-switched network (PSN) infrastructures (e.g., those based on Internet Protocol (IP) addressing) as a replacement for, or as an adjunct to, the existing circuit-switched network (CSN) infrastructures used in today's telephony. From the network operators' perspective, the inherent traffic aggregation in packet-switched infrastructures allows for a reduction in the cost of transmission and the infrastructure cost per end-user. Ultimately, such cost reductions enable the network operators to pass on the concomitant cost savings to the end-users.
Some of the market drivers that impel the existing Voice-over-IP (VoIP) technology are: improvements in the quality of IP telephony; the Internet phenomenon; emergence of standards; cost-effective price-points for advanced services via media-rich call management, et cetera. Some of the emerging standards in this area are the well-known H.323 protocol, developed by the International Telecommunications Union (ITU), Session Initiation Protocol (SIP) or Internet Protocol Device Control (IPDC) by the Internet Engineering Task Force (IETF), or Simple/Media Gateway Control Protocol (SGCP or MGCP). Using these IP standards, devices such as personal computers can inter-operate seamlessly in a vast inter-network, sharing a mixture of audio, video, and data across all forms of packet-based networks which may interface with circuit-switched network portions.
As is well-known in the telecommunications industry, services and service provisioning are the raison d'ètre of a telecommunications network, including VoIP networks. Services are typically categorized into (i) “basic services” (i.e., services which allow basic call processes such as call establishment and termination) or (ii) “advanced services” which are also commonly referred to as Value-Added Services (VAS). It is also well-known that advanced services operate as factors for market differentiation and are crucial for network operators' (or service providers') success.
Because of the integration of PSNs and CSNs, two approaches are available for providing Value-Added Services (also known in H.323-based VoIP networks as Supplementary Services) in VoIP networks. The IP-based VAS architecture is based on the notion that because telephony call control logically resides within the end terminals of the network, service implementation should preferably be localized therein also. This architecture makes terminals the primary actors for IP VAS. On the other hand, there exists an Intelligent Network (IN) or Wireless IntelligentNetwork (WIN) service architecture for providing VAS in the context of CSNs. The WIN/IN service architecture is network-centric, that is, service implementation is done in the network, with centralized service logic in a service node (e.g., a Service Control Point or SCP) that is accessed by switching entities. Applied to IP telephony, this implies access from such entities as gatekeepers (in H.323 networks) or proxy/redirect servers (in SIP networks).
It should be apparent to those skilled in the art that each of the VAS approaches set forth above has its own shortcomings and deficiencies. For instance, in IP-based VAS architectures, a significant concern is that the architecture does not address service mobility (i.e., end-user can access the services regardless of the terminal/appliance used). Also, typically a small number of services are provided in these approaches, which tend to be rather simple as well. Further, as the number of services available increases, the issue of service interaction becomes more significant because there is no centralized logic for resolving contentions or conflicts among the services.
In the case of WIN/IN service architectures, a principal drawback is the complexity of the CSN itself. Also, another significant shortcoming is that network-based service architectures do not scale reliably as the number of available services keeps increasing.
As is well known, there have been several VAS solutions, depending upon the particular standard used in IP telephony. For example, the H.323 standard comes equipped with the H.450 protocol for Supplementary Services (SS). Similarly, there are solutions such as Call Processing Language (CPL) for the SIP-based IP telephony. Also, there exist Application Programming Interface (API)-based solutions such as, e.g., Parlay, VHE/OSA, etc.
However, it should be appreciated by those of ordinary skill in the art that several shortcomings and weaknesses exist in the state-of-the-art service provisioning schemes in VoIP networks, regardless of whether they are H.323-based, SIP-based, or otherwise. For example, none of the solutions is complete or fully satisfactory per se. Service invocation is usually not addressed in these solutions. If addressed at all, service invocation capabilities are rather limited and poorly provided. Further, each solution is a “closed” entity in that it does not permit the integration of other solutions, either existing or yet to come.
Based on the foregoing, it is apparent that there has arisen an acute need for a service provisioning architecture for use within the context of the burgeoning VoIP technology which overcomes these and other shortcomings and deficiencies of the current IP- and WIN/IN-based service architectures. The present invention provides such a solution.